FOXBORO, Mass. — Even with a year remaining on his contract, Andre Carter knew it would be better if he and the Redskins could agree to part ways last offseason on the eve of the NFL lockout.

It was a tremendous gamble, and there was a point over the summer when Carter thought the decision to leave Washington had resulted in the end of his career. Teams grew more reluctant to add older free agents to their roster as training camp progressed, and the 32-year-old Carter thought he was done.

“I really did,” Carter said Wednesday.

Carter and the Redskins’ new defensive scheme under head coach Mike Shanahan just didn’t mesh in 2010. He was converted from a 4-3 right defensive end into a 3-4 left outside linebacker. Carter welcomed the position change because he’s a team-first guy, but he struggled with the overload of new concepts, particularly in pass coverage.

“To that respect, I’m very thankful to learn that particular position, but in the end, I knew it just wasn’t right for me,” said Carter, who will get his first chance to line up against the Redskins on Sunday.

“They knew it, too, but they appreciated my hard work, and I never complained. I just went out there day by day. At the end, we shook hands. It was a mutual agreement on both terms. There was no harm, no foul, just two men — or myself and the organization — knowing, ‘thank you, but time to move on to the next chapter.'”

Carter holds no ill will whatsoever toward the Redskins, who were building the defense around outside linebacker Brian Orakpo as they tried to get younger. And while Carter initiated the conversation with the front office, it definitely turned out to be a mutual decision, as each side understood it would be best to head in a different direction.

The lockout appeared to derail Carter’s new chapter, though. The Giants courted him once free agency began, but they couldn’t agree to the terms of the contract.

Eventually, the Patriots became the only other team to reach out to Carter, and the two sides came to terms on a one-year contract with a base salary of $1.75 million plus $1 million in reported incentive clauses.

Obviously, the marriage has worked tremendously, as Carter has a team-best nine sacks through 12 games, which is tied for the ninth most in the NFL. With one more sack, Carter would become just the third player of Bill Belichick‘s tenure with the Patriots to reach double-digit sacks in a single season (Mike Vrabel had 12 1/2 in 2007, and Tully Banta-Cain had 10 in 2009).

“Everything I’ve done has been such a blessing, to be here, to get picked up, because I tell everybody I thought I was actually done coming into this season,” Carter said. “Just to be productive and just to have fun to play the game I’ve been blessed to play for so many years is just a wonderful feeling.”

Carter hasn’t hit the quarterback in the last two games, which was surprising on the heels of a three-game stretch when he recorded 14 quarterback hits. The Patriots’ defensive scheme was different against the Colts, though, as Carter was assigned to play more 3-technique — lining up between the guard and tackle and attacking through the B-gap — than at any other point in the season. It helped free up other rushers, like defensive tackle Kyle Love to the inside and safety James Ihedigbo on the outside, and Carter knew it was also a positive tool to counter Indianapolis’ running game.

Carter shifted to the 5-technique — lining up over the outside shoulder of the tackle — a little more frequently later in the game, and he had more success with that assignment. But Carter wasn’t complaining about the game plan, noting there have been wide receivers playing defense and the whole team has been all in on the march to find success.

“I’m just happy to see other guys playing well,” Carter said. “That’s what you do. You celebrate with your teammates because this is a team sport.”